1. Field of the Invention
The present invention relates, in general, to monoclonal antibodies. In particular, the present invention relates to monoclonal antibodies that recognize Friend murine leukemia virus.
2. Background Information
Several monoclonal antibodies which react with the Friend murine leukemia virus (F-MuLV) and related retroviruses have been produced (CHESEBRO, B. et al. (1983a) Virology 127, 134-148). These antibodies have been used to titrate and distinguish a mixture of ecotropic F-MuLV and dual-tropic Friend mink cell focus-inducing (MCF) viruses in a focal infectivity assay (FIA) using indirect membrane immunofluorescence to detect foci of infected live cells (SITBON, M. et al. (1985) Virology 141, 110-118). However, with immunofluorescence microscopy it has often been difficult to find low power (10xc3x97) objectives with sufficient light gathering capacity to facilitate visualization of foci. Higher magnifications can be used, but this greatly increases the labor of scanning culture wells to count foci of viral infection. These problems can be overcome by using immunoperoxidase, rather than immunofluorescence in the detection of foci, but in this situation it is desirable to carry out tests on methanol-fixed cells both to eliminate endogenous peroxidase and to allow detection of antigens in the cytoplasm of infected cells. Furthermore, the use of fixed cells aids greatly in the convenience of performing assays since multiple assays can be prepared and stored for processing at a later time. However, monoclonal antibodies generated against protein antigens in their native state frequently will not recognize the viral antigens after fixation.
The present invention provides monoclonal antibodies selected specifically for reactivity with methanol-fixed viral antigens. These monoclonal antibodies were shown to be highly effective in titration of virus by a focal infectivity assay using an indirect immunoperoxidase detection system. In addition, one of these antibodies was found to be very useful in immunohistochemical detection of viral antigen by light microscopy and immunoelectronmicroscopy.
It is an object of the invention to provide hybridomas capable of producing monoclonal antibodies specific for antigenic sites on methanol-fixed F-MuLV infected cells.
It is another object of the invention to provide monoclonal antibodies that recognize epitopes of a Friend murine leukemia virus specific antigen.
It is a further object of the invention to provide diagnostic test kits comprising the above-described monoclonal antibodies.
These objects, and others which will be apparent to those skilled in the art from the following detailed description, have been accomplished by providing novel monoclonal antibodies which are specific for antigens characteristic of methanol-fixed F-MuLV infected cells.
In one embodiment, the present invention relates to hybridomas, resulting from the fusion of myeloma cells and spleen cells, which produce Friend murine leukemia virus specific monoclonal antibodies that form an immune complex with antigenic determinants of methanol-fixed F-MuLV infected cells.
In another embodiment, the present invention relates to Friend murine leukemia virus specific monoclonal antibodies specific for an antigenic determinant characteristic of a methanol-fixed F-MuLV infected cell.
In a further embodiment, the present invention relates to a diagnostic kit comprising
i) the above-described monoclonal antibodies, and
ii) a conjugate comprising a binding partner of the monoclonal antibody and a label; alternatively the kit can comprise a conjugate comprising the above-described monoclonal antibody and the label.